eternal-abyss-77

eternal-abyss-77 OP t1_iwg7mjm wrote

I am asking what is

I - H is?

I get the same H as you say, but what is the matrix we get after I - H? Is it a mirror of H? As in paper, they said

I  -I
-I  I

So, the I in I-H is, normal identity matrix where major diagonal elements are 1 or is it mirror of H

1

eternal-abyss-77 OP t1_iwg5fm0 wrote

> Yes, I is the identity matrix.

> The shift matrix, H, will not have a row or column with only zeros in it. If l is 2 and N is 7 then H(1, 3) (1 based?) will be a 1 and the start of a diagonal.

> You have similarly misunderstood equation 4. There will not be a row or column with only 0s in it.

Hl is this

[ 0 0 0 0 0 1 0 ]
[ 0 0 0 0 0 0 1 ]
[ 0 0 0 0 0 0 0 ]
[ 0 0 0 0 0 0 0 ]
[ 0 0 0 0 0 0 0 ]
[ 1 0 0 0 0 0 0 ]
[ 0 1 0 0 0 0 0 ]

I - Hl is ?

[ 1 0 0 0 0 -1 0 ]
[ 0 1 0 0 0 0 -1 ]
[ 0 0 0 0 0 0 0 ]
[ 0 0 0 0 0 0 0 ]
[ 0 0 0 0 0 0 0 ]
[ -1 0 0 0 0 1 0 ]
[ 0 -1 0 0 0 0 1 ]

Or

[ 1 0 0 0 0 -1 0 ]
[ 0 1 0 0 0 0 -1 ]
[ 0 0 1 0 0 0 0 ]
[ 0 0 0 1 0 0 0 ]
[ 0 0 0 0 1 0 0 ]
[ -1 0 0 0 0 1 0 ]
[ 0 -1 0 0 0 0 1 ]

?

Show me how the matrix is written

And elaborate this:

> The authors do not mention rotation at all in this paper. They do mention that gradients are computed along those directions by the pixel differences.

1

eternal-abyss-77 OP t1_iwfxk5b wrote

Ok I'll ask you exactly what i don't understand.

In equations 2 and 4 there is I which represents Identity matrix right?

So if let's say l = 2 and N = 7

Now will the shift matrix be like

[ 0 0 0 0 0 1 0 ]
[ 0 0 0 0 0 0 1 ]
[ 0 0 0 0 0 0 0 ]
[ 0 0 0 0 0 0 0 ]
[ 0 0 0 0 0 0 0 ]
[ 1 0 0 0 0 0 0 ]
[ 0 1 0 0 0 0 0 ]

If yes, then

[ I  -I ]
[-I   I ]

Should be of the form,

[ 1 0 0 0 0 -1 0 ]
[ 0 1 0 0 0 0 -1 ]
[ 0 0 0 0 0 0 0 ]
[ 0 0 0 0 0 0 0 ]
[ 0 0 0 0 0 0 0 ]
[ -1 0 0 0 0 1 0 ]
[ 0 -1 0 0 0 0 1 ]

Or

[ 1 0 0 0 0 -1 0 ]
[ 0 1 0 0 0 0 -1 ]
[ 0 0 1 0 0 0 0 ]
[ 0 0 0 1 0 0 0 ]
[ 0 0 0 0 1 0 0 ]
[ -1 0 0 0 0 1 0 ]
[ 0 -1 0 0 0 0 1 ]

?

Be it horizontal shift or vertical shift.

And what do they mean by rotations here : 0°, 45°, 90°, 135° ?

Because I'm extending this idea, so I am asking community help, perspectives, opinions and understandings, so I may not be wrongly understanding math.

1

eternal-abyss-77 OP t1_iwfx6f4 wrote

Ok I'll ask you exactly what i don't understand.

In equations 2 and 4 there is I which represents Identity matrix right?

So if let's say l = 2 and N = 7

Now will the shift matrix be like

[ 0 0 0 0 0 1 0 ]
[ 0 0 0 0 0 0 1 ]
[ 0 0 0 0 0 0 0 ]
[ 0 0 0 0 0 0 0 ]
[ 0 0 0 0 0 0 0 ]
[ 1 0 0 0 0 0 0 ]
[ 0 1 0 0 0 0 0 ]

If yes, then

[ I  -I ]
[-I   I ]

Should be of the form,

[ 1 0 0 0 0 -1 0 ]
[ 0 1 0 0 0 0 -1 ]
[ 0 0 0 0 0 0 0 ]
[ 0 0 0 0 0 0 0 ]
[ 0 0 0 0 0 0 0 ]
[ -1 0 0 0 0 1 0 ]
[ 0 -1 0 0 0 0 1 ]

Or

[ 1 0 0 0 0 -1 0 ]
[ 0 1 0 0 0 0 -1 ]
[ 0 0 1 0 0 0 0 ]
[ 0 0 0 1 0 0 0 ]
[ 0 0 0 0 1 0 0 ]
[ -1 0 0 0 0 1 0 ]
[ 0 -1 0 0 0 0 1 ]

?

Be it horizontal shift or vertical shift.

And what do they mean by rotations here : 0°, 45°, 90°, 135° ?

Because I'm extending this idea, so I am asking community help, perspectives, opinions and understandings, so I may not be wrongly understanding math.

−1

eternal-abyss-77 OP t1_iwfu277 wrote

Sir, firstly thanks for responding.

I already have implemented this as a working program. But now I am enhancing it, and I have some feeling that I somehow am missing something from the paper, and not understanding it properly.

For example:

The equations [2, 4, 6, 8, 10, 15-18] in pages 3, 4 and 5

The training of the model with generated features with Linear LSE mentioned in page 6-7

And section B Local pixel difference descriptor, para 2 regarding directions. And it's related figures, Figure 3(a,b).

If you can explain these things, i can effectively understand your explanation and ask my doubts wrt my present work on this paper, with code.

−1

eternal-abyss-77 OP t1_iwfpfz7 wrote

Sir, firstly thanks for responding.

I already have implemented this as a working program. But now I am enhancing it, and I have some feeling that I somehow am missing something from the paper, and not understanding it properly.

For example:

The equations [2, 4, 6, 8, 10, 15-18] in pages 3, 4 and 5

The training of the model with generated features with Linear LSE mentioned in page 6-7

And section B Local pixel difference descriptor, para 2 regarding directions. And it's related figures, Figure 3(a,b).

If you can explain these things, i can effectively understand your explanation and ask my doubts wrt my present work on this paper, with code.

0